Bucu was excavated by archaeologists in the 1970s. Recovery excavations at the Kleine Gröpelgrube unearthed a nearby settlement, the suburbium, in 1997. The exposed findings indicate that the region east of the castle was inhabited by Slavs from the 8th or 9th century until the middle of the 12th century.
In a southern section of the current Große Burgstraße, a 3.5 m wide and 2.5 m deep trench protected the settlement. The northern border was presumably north of the current Königstraße. To the west the settlement bordered the castle directly, while to the east it reached the Wakenitz. The settlement area was probably about 6 ha. Discoveries in the interior include mines, mining houses, hearths, and a great number of ceramic objects. The remnants of a potter's workshop were found in the Kleine Gröpelgrube. A Slavic pottery tradition could have existed at the location until the arrival of Saxons in the 12th century. The Kleine Gröpelgrube was first mentioned in 1297 as parva platea lutifigulorum, or the small street of the loam potters.
